Noise texture not working on two planes at same time
You have two objects selected in Object Mode. The actual selected object is the one highlighted in a lighter orange. That is a) the last object selected and b) the Active object. You are seeing the Material attached to the active object. 

As you can see in this screenshot, I have both objects selected as you do, and it appears that both have the same Material, but they do not.



If I invert the order in which I select the two objects, making the top plane the active object, you can see that the material is, in fact, different.



Select just the topmost plane and see what changes in the Material Editor.